Amperometric sensor for ascorbic acid using a gold electrode modified with ZnO@SiO2 nanospheres
Abstract
Here we report a facile synthesis of ZnO coated SiO2 (ZnO@SiO2) nanospheres as high-performance sensing materials for ascorbic acid (AA). ZnO nanospheres were first prepared by a hydrothermal method and then SiO2 was coated over the ZnO nanospheres by a sol–gel process. The sensing properties of the ZnO@SiO2 nanospheres were explored, and it was demonstrated that the ZnO@SiO2 nanospheres are responsive for AA. By comparing the sensing ability of ZnO with ZnO@SiO2 nanospheres, it was deduced that ZnO@SiO2 nanospheres are much more sensitive towards AA as compared to ZnO. The results revealed that ZnO@SiO2 nanospheres have a remarkable sensitivity (0.2232 mA mM−1 cm−2) toward AA with a wide range (0.1–1.5 mM) of detection and a lower limit of detection (64.5 μM). The performance of the sensor was additionally optimized by different scan rates. Thus, ZnO@SiO2 nanospheres could be a prospective material for the production of a sensitive and competent AA sensor.